The question of whether or not patients who fail to respond to or incompletely respond to etanercept can still respond to infliximab has potentially important therapeutic implications. Evidence that such patients respond to infliximab could support the notion that these agents have important differences in their mechanisms of action, or could be explained by the presence of antibodies to etanercept. More importantly, it would suggest that therapeutic failure of one TNFa-blocker does not necessarily predict failure of all TNFa-targeting agents. Such a finding could open important therapeutic alternatives to RA patients and is of clear importance because this class of biologics (biologic agent) represents the most significant advance to date in the treatment of RA.